Device for dosing urea in blood and in urine



Aug. 18, 1953 F. P. MASI-:Lus 2,649,359

DEVICE FOR DOSING UREA IN BLOOD AND IN URINE Filed may 7, 1951 Fig.2

nulmll m Patented Aug. 18, 1953 iii-3; 25;; :1i

D Evrcs Fon DosING UREA 1N LooDl AND 1N URINE Francesco Paolo Masellis, Rome, Italy, assigner to Aesculapiusfl S.` r.,l., Milan, Italy, arfirm Application May 7, 19-51, Serial No. 224,970 `In Italy September 30, 1950 Y' 4 claims. (o1. .gs- 254) The present invention relates to a device for determining azotaemia or for dosing urinary urea, by means of a reaction with sodium hypobromite. The device accurately measures the evolved gases volumetrically.

It is an object of the invention to provide a device easy to be employed, which does not require the use of tables or complicated calculations and is useful to furnish the data requested by means of a mere volumetric measurement and the knowledge of a numeric coeicient, which is a function of the very device, yielding an approximation sufficient for clinical needs.

It is known now to be complicated to `use the various apparatuses employed at present for determining the values in question, and it is also known that said apparatuses are in general useful either for determining azotaemia or for determining the rate of urinary urea.

A further object of the invention is to provide a device which alone is adapted for measuring either of said values as needed.

According to this invention a device is provided With a horizontal reaction chamber of substantially cylindrical shape at the ends of which are branched oir two ascending pipes.

One of said pipes has a cock that can be operated from outside, while the other pipe, which is parallel to the rst one in its initial section, is

united to the iirst with a substantially horizontal cross-piece, from which originates a pipe with two diameters, open at its free end, graduated, adapted to serve as a barometric column, viz. to give under conditions of constant pressure, the measure of an expanding gas volume, by the modification of the height of a liquid column contained in said pipe by the pressure of gases evolved in the apparatus.

The pipe provided with a cock, is further closed at its free end with a ground glass stopper, of standardized dimensions, provided with a hole or channel for controlled venting of the reaction chamber to the atmosphere through the bent pipe, if the barometric column is full of liqui-d, and the intercepting cock of the rst pipe is closed.

One preferred form of embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 represents a front elevation of the device, and

Fig. 2 represents a side elevation of the same device.

With reference to the drawing, the device comprises the reaction chamber l in horizontal posii 2 tion, at the ends of which are provided the two vertical pipes 2 and 3.

The pipe .2 presents in the proximity of the reaction chamber l, the cock 4, above which the said pipe has the shape of a cylindrical test tube 5, of larger diameter, joined to said cock 4. f

The upper part of the test tube 5 is closed by an inside hollow stopper 6 of standardized dimensions and provided with a lateral hole l used to vent the interior of the tube 5 with the outside', through a corresponding hole I2 in the side Wall of the tube 5.

In the proximity of the .upper end of the tube 5, is connected thereto the horizontal cross-piece il,k which constitutes an extension of the pipe 3.

About at the middle of the cross-piece B'there is branched off the pipe 9, which constitutes a barometric column'and which comprises an upper part l0 of smaller diameter graduated with a zero graduation at a` certain ldistance from the branching oil point of vthe cross-'piece 8, and a lower part Il of larger diameter, which too is graduated.

Each graduation of the upper section I 0 corresponds to 1/50 cc. and each graduation of the lower section Il corresponds to 1/10 cc.

It is important to note that the dimensions of the tube 5 are such as to permit to introduce into said tube the pipette containing the liquidg'with which the requested determination is to be carred out, as far as to insert its end into the duct of the cock 4. In this way, traces of the liquid to be examined are prevented from depositing on the inner walls of the tube 5 and from reacting thus too early with the sodium hypobromite to be employed for the reaction.

The apparatus according to the invention is employed as follows:

Remove the stopper 6 and by means of a pipette, after having opened the cock 4, introduce into the chamber l for instance 2 cc. of haemel ltrate; then add 1 cc. of 10% sodium hydroxide solution. Close the cock 4 and introduce into the tube 5, 4 to 5 cc. of sodium hypobromite.

Then place the stopper 6 in such a manner that its duct 1 puts the chamber l in communication with the outside through the pipes 3 and 8, and immerse the whole into a vessel of sumcient height full of water, until said water on rising in the barometric column reaches the zero graduation.

Rotate the stopper 6 so as to break the communication between the outside and the reaction chamber, lift if needed the device from the vesthe barometric column the volume of gaslde-lV veloped, which volume multiplied by arfixed co eicient, being a function of :the'devicerwith which the operation is carried out, and ofthe' quantities of reagent playing, furnishesffthepercentage of urea to be ascertained. l. y K

The present invention has 'been illustrated and described in a preferred'form of embodiment, but it is understood that constructive variants may'be provided in practice without departing from the scope of the present patent.

Having now particularly described and ascertained the nature ofmy said invention and in what manner the same is to be performed, I declare that what I claim is: Y

1. Volumetric gas analytical devicecomprising a horizontally mountedreaction chamber, avert-ically mounted fluid supply chamber communieating with one end of said reaction chamber, said fluid supply chamber having'a stop cock mounted rat its lower endfor ,control of fluid passage to said reaction chamber, a. graduated volumetric burette mounted invertedly vertically upon said'apparatus with an open end extending downwardly therefrom and the opposite end communicating with the upper'horizontal portionlof said reaction chamber, and additional valve means for venting said reaction chamber and burette to the atmosphere.

2. Apparatus as defined in claim l, wherein the burette comprises an elongated cylindrical tube in which the lowermost depending portion is of relatively wide diameter with large volumetric calibrations thereon and the upper portion of said burette communicating with the relactionchamberand with the large diameter depending portion of said burette'is ofrelatively small diameter with fine volumetric calibrations thereon.

.rApparatusas defined in claim 1, wherein `said vertically mounted supply chamber is of suicient large diameter to insert a pipette directly AYirxtothefvalve:"opening mounted in the bottom 15'-y thereof.

-4Apparatusas defined in claim l, wherein VVAsaid.vertically mounted fluid supply chamber has rotatame stopper fitted gas-tight therein, said v stopperr and said upper. end of said fluid supply FRAN CESCO PAOLO MASELLIS.

:References-.cited in me: mehr this patent UNITED STATES 'PATENTS Number Name Date v :715046,259 Bunzel Dec.13, 1912 1,074,795 Johnson Oct. 7, 1913 2,089,796 v.Hopf ett al Aug. l0, 193? OTHER REFERENCES `Catalogue, Schaar and Co., No. 50;'May. 9,1950, Figs. B66880 and G2030, pages 71 and.324. 

1. VOLUMETRIC GAS ANALYTICAL DEVICE COMPRISING A HORIZONTALLY MOUNTED REACTION CHAMBER, A VERTICALLY MOUNTED FLUID SUPPLY CHAMBER COMMUNICATING WITH ONE END OF SAID REACTION CHAMBER, SAID FLUID SUPPLY CHAMBER HAVING A STOP COCK MOUNTED AT ITS LOWER END FOR CONTROL OF FLUID PASSAGE TO SAID REACTION CHAMBER, A GRADUATED VOLUMETRIC BURETTE MOUNTED INVERTEDLY VERTICALLY UPON SAID APPARATUS WITH AN OPEN END EXTENDING DOWNWARDLY THEREFROM AND THE OPPOSITE END COMMUNICATING WITH THE UPPER HORIZONTAL PORTION OF SAID REACTION CHAMBER, AND ADDITIONAL VALVE MEANS FOR VENTING SAID REACTION CHAMBER AND BURETTE TO THE ATMOSPHERE. 